If I had a job which did not pay particularly well, which appeared to offend everyone who comes into contact with me and if I got wrong, could cause a tragedy for which I would probably be blamed, I might have the odd "off-day" as well.
I have made mention previously of the high standard at Narita and would be delighted if this could be copied elsewhere but it won't be because you can't change culture so easily. Despite the problems, overall I think the UK security people do a good job especially when compared to the TSA standard.
I came through T5 earlier this week and I was most impressed by the patience and helpful manner that the scanner team displayed.